Phthalocyanine and use of phthalocyanine as a marking agent

ABSTRACT

Phthalocyanines of the formula                    
     where 
     Me is twice hydrogen, twice lithium, magnesium, zinc, copper, nickel, VO, TiO, AlCl, AlOH, AlOCOCH 3 , AlOCOCF 3 , SiCl 2  or Si(OH) 2 , 
     at least four of the radicals R 1  to R 16  are each independently of the others a five- or six-membered saturated nitrogen-containing heterocyclic radical which is bonded to the phthalocyanine structure via a ring nitrogen atom and which can additionally contain further hetero atoms, and 
     any remaining radicals R 1  to R 16  are each hydrogen, halogen, hydroxysulfonyl or C 1 -C 4 -dialkylsulfamoyl, 
     subject to the proviso that tetrakispiperidinylphthalocyanine shall be excluded, 
     and heterocyclyl-substituted phthalocyanines are useful for marking liquids, in particular mineral oils.

This application is a 371of PCT/EP98/02824 filed May 13, 1998.

The present invention relates to novel phthalocyanines of the formula I

where

Me is twice hydrogen, twice lithium, magnesium, zinc, copper, nickel,VO, TiO, AlCl, AlOH, AlOCOCH₃, AlOCOCF₃, SiCl₂ or Si(OH)₂,

at least four of the radicals R¹ to R¹⁶ are each independently of theothers a five- or six-membered saturated nitrogen-containingheterocyclic radical which is bonded to the phthalocyanine structure viaa ring nitrogen atom and which can additionally contain one or twofurther nitrogen atoms or a further oxygen or sulfur atom, and

any remaining radicals R¹ to R¹⁶ are each hydrogen, halogen,hydroxysulfonyl or C₁-C₄-dialkylsulfamoyl,

subject to the proviso that tetrakispiperidinylphthalocyanine shall beexcluded,

to the use of heterocyclyl-substituted phthalocyanines for markingliquids, and to mineral oils comprising such phthalocyanines.

J. Gen. Chem. USSR, 51 (1981), 1405-1411, discloses the preparation oftetrakispiperidinylphthalocyanine. WO-A-94/02570 and WO-A-96/10620describe phthalocyanines as markers for liquids, especially mineraloils.

However, it has been found that the markers described therein still havedefects in their application properties, especially insufficientsolubility and insufficient chemical stability in solution.

It is an object of the present invention to provide suitablephthalocyanines having an improved property profile.

We have found that this object is achieved by the phthalocyanines of theformula I more particularly defined at the beginning.

Any alkyl appearing in the formulae mentioned herein may bestraight-chain or branched.

Halogen is for example fluorine, chlorine, bromine or iodine.

C₁-C₄-Dialkylsulfamoyl is for example dimethylsulfamoyl,diethylsulfamoyl, dipropylsulfamoyl, diisopropylsulfamoyl,dibutylsulfamoyl or N-methyl-N-ethylsulfamoyl.

Suitable five- or six-membered saturated nitrogen-containingheterocyclic radicals which are attached to the phthalocyanine structurevia a ring nitrogen atom and can additionally contain one or two furthernitrogen atoms or a further oxygen or sulfur atom in the ring arederived for example from pyrrolidine, pyrazolidine, imidazolidine,oxazolidine, isoxazolidine, piperidine, piperazine, morpholine orthiomorpholine as basic structure.

The heterocyclic radicals can be monosubstituted or polysubstituted,preferably monosubstituted, disubstituted or trisubstituted, especiallymonosubstituted. Preferred substituents are C₁-C₄-alkyl, benzyl,phenylethyl or phenyl.

Suitable heterocyclic radicals are for example pyrrolidin-1-yl, 2- or3-methylpyrrolidin-1-yl, 2,4-dimethyl-3-ethylpyrrolidinyl,pyrazolidin-1-yl, 2-, 3-, 4- or 5-methylpyrazolidin-1-yl,imidazolidin-1-yl, 2-, 3-, 4- or 5-methylimidazolidin-1-yl,oxazolidin-3-yl, 2-, 4- or 5-methyloxazolidin-3-yl, isoxazolidin-2-yl,3-, 4- or 5-methylisoxazolidin-2-yl, piperidin-1-yl, 2-, 3-, 4-methyl-,-ethyl- or -benzyl-piperidin-1-yl, 2,6-dimethylpiperidin-1-yl,piperazin-1-yl, 4-(C₁-C₄-alkyl)piperazin-1-yl, such as 4-methyl- or4-ethylpiperazin-1-yl, morpholin-4-yl, thiomorpholin-4-yl orthiomorpholin-4-yl S,S-dioxide.

Preferred heterocyclic radicals are derived from pyrrolidine,piperidine, piperazine or morpholine as basic structure.

Preference is given to phthalocyanines of the formula I wherein four ofthe radicals R¹ to R¹⁶ are each a heterocyclic radical.

Preference is further given to phthalocyanines of the formula I whereinfour of the radicals R¹ to R¹⁶ are each a heterocyclic radical and theremaining radicals R¹ to R¹⁶ are each hydrogen.

Preference is further given to phthalocyanines of the formula I whichhave heterocyclic radicals which are monosubstituted or polysubstituted,preferably monosubstituted, disubstituted or trisubstituted, especiallymonosubstituted, by C₁-C₄-alkyl, benzyl, phenylethyl or phenyl.

Preference is given to phthalocyanines which conform to the formula Iaor Ib

where

the radicals R⁴, R⁸, R¹² and R¹⁶ and also R², R⁶, R¹⁰ and R¹⁴ are each aheterocyclic radical and Me is in each case as defined above, and alsotheir positional isomers in relation to the radicals R⁴, R⁸, R¹² and R¹⁶and also R², R⁶, R¹⁰ and R¹⁴.

Of particular interest are phthalocyanines of the formula Ia or Ib,where R⁴, R⁸, R¹² and R¹⁶ and also R², R⁶, R¹⁰ and R¹⁴ are eachpyrrolidin-1-yl, piperidin-1-yl, piperazin-1-yl or morpholin-4-yl, whichradicals can be monosubstituted, disubstituted or trisubstituted,preferably monosubstituted, by C₁-C₄-alkyl, benzyl, phenylethyl orphenyl.

Preference is also given to phthalocyanines of the formula I in whichthe substituents are selected from a combination of the above-recitedpreferred substituents.

The novel phthalocyanines of the formula I are obtainable in aconventional manner, for example as described in J. Gen. Chem. USSR 51(1981) 1405-1411, F. H. Moser, A. L. Thomas, The Phthalocyanines, CRCPress, Boca Rota, Fla., 1983, or J. Am. Chem. Soc. 106 (1984) 7404-7410.For instance, phthalonitriles which, in conformance with the formula I,bear suitable substituents can be made to react in an inert diluent inthe presence of a base, optionally in the presence of a metallizingreagent.

The present invention further provides for the use of phthalocyanines ofthe formula II

where

Me is twice hydrogen, twice lithium, magnesium, zinc, copper, nickel,VO, TiO, AlCl, AlOH, AlOCOCH₃, AlOCOCF₃, SiCl₂ or Si(OH)₂,

at least four of the radicals R¹ to R¹⁶ are each independently of theothers a five- or six-membered saturated nitrogen-containingheterocyclic radical which is bonded to the phthalocyanine structure viaa ring nitrogen atom and which can additionally contain one or twofurther nitrogen atoms or a further oxygen or sulfur atom, and

any remaining radicals R¹ to R¹⁶ are each hydrogen, halogen,hydroxysulfonyl or C₁-C₄-dialkylsulfamoyl,

as markers for liquids.

Preference is given to the use of phthalocyanines of the formula Iwherein four of the radicals R¹ to R¹⁶ are each a heterocyclic radical.

Preference is further given to the use of phthalocyanines of the formulaI wherein four of the radicals R¹ to R¹⁶ are each a heterocyclic radicaland the remaining radicals R¹ to R¹⁶ are each hydrogen.

Preference is further given to the use of phthalocyanines of the formulaI which have heterocyclic radicals which are monosubstituted orpolysubstituted, preferably monosubstituted, disubstituted ortrisubstituted, especially monosubstituted, by C₁-C₄-alkyl, benzyl,phenylethyl or phenyl.

Particular preference is given to the use of phthalocyanines whichconform to the formula Ia or Ib

where

the radicals R⁴, R⁸, R¹² and R¹⁶ and also R², R⁶ ₁ R¹⁰ and R¹⁴ are eacha heterocyclic radical and Me is in each case as defined above, and alsotheir positional isomers in relation to the radicals R⁴, R⁸, R¹² and R¹⁶and also R², R⁶, R¹⁰ and R¹⁴.

Of particular interest is the use of phthalocyanines of the formula Iaor Ib, where R⁴, R⁸, R¹² and R¹⁶ and also R², R⁶, R¹⁰ and R¹⁴ are eachpyrrolidin-1-yl, piperidin-1-yl, piperazin-1-yl or morpholin-4-yl, whichradicals can be monosubstituted, disubstituted or trisubstituted,preferably monosubstituted, by C₁-C₄-alkyl, benzyl, phenylethyl orphenyl.

It is frequently necessary to mark liquids in order that the liquidsthus marked may be detected later, for example in use, by means ofsuitable methods.

In this way it is possible, for example, to distinguish fuel oil anddiesel oil.

Suitable solvents for marking according to the invention by means of thecompounds more particularly defined above are especially organicliquids, for example alcohols, such as methanol, ethanol, propanol,isopropanol, butanol, isobutanol, sec-butanol, pentanol, isopentanol,neopentanol or hexanol, glycols, such as 1,2-ethylene glycol, 1,2- or1,3-propylene glycol, 1,2-, 2,3- or 1,4-butylene glycol, di- ortriethylene glycol or di- or tripropylene glycol, ethers, such as methyltert-butyl ether, 1,2-ethylene glycol monomethyl or dimethyl ether,1,2-ethylene glycol monoethyl or diethyl ether, 3-methoxypropanol,3-isopropoxypropanol, tetrahydrofuran or dioxane, ketones, such asacetone, methyl ethyl ketone or diacetone alcohol, esters, such asmethyl acetate, ethyl acetate, propyl acetate or butyl acetate,aliphatic or aromatic hydrocarbons such as pentane, hexane, heptane,octane, isooctane, petroleum ether, toluene, xylene, ethylbenzene,tetralin, decalin, dimethylnaphthalene, mineral spirit, mineral oils,such as gasoline, kerosene, diesel oil or fuel oil, natural oils, suchas olive oil, soybean oil or sunflower oil, or natural or syntheticengine, hydraulic or gear oils, for example vehicle engine oil or sewingmachine oil, or brake fluids.

The abovementioned compounds are particularly useful for marking mineraloils where some form of identification is mandatory, for example for taxreasons. To keep the costs for this to a minimum, it is usuallydesirable to use very high yield dyes for the coloring. However, evenso-called strong dyes are no longer detectable purely visually in highdilution in mineral oils.

Based on the weight of the liquid to be marked, from 1 to 1000 ppb,preferably from 1 to 500 ppb, especially from 100 ppb to 500 ppb, ofphthalocyanine II are used.

To mark the liquids, especially mineral oils, the phthalocyanines of theformula II are generally employed in the form of solutions. Suitablesolvents are preferably aromatic hydrocarbons, such asC₁-C₂₀-alkyl-substituted aromatic hydrocarbons, for example toluene,xylene or Shellsol® (from Shell). To avoid the resulting solutionshaving an excessively high viscosity, the concentration ofphthalocyanine II is generally chosen within the range from 0.5 to 60%by weight, based on the solution.

The present invention further provides mineral oils comprising one ormore phthalocyanines of the formula II.

The phthalocyanines II generally have their absorption maximum withinthe range from 600 to 1200 nm and/or fluoresce within the range from 620to 1200 nm and are thus easy to detect using suitable instruments.

The detection of the phthalocyanines II can be effected in aconventional manner, for example by measuring the IR absorption spectrumof the liquids to be examined.

However, it is also possible to excite the fluorescence of thephthalocyanines II present in the liquids, advantageously using asemiconductor laser or a semiconductor diode. It is particularlyadvantageous to employ a semiconductor laser or diode having a maximumemission wavelength within the spectral region from λ_(max) −100 nm toλ_(max) +20 nm. Here λmax is the wavelength of the absorption maximum ofthe marker. The maximum emission wavelength is within the range from 620to 1200 nm.

The fluorescence light thus generated is advantageously detected using asemiconductor detector, especially with a silicon photodiode or agermanium photodiode.

Detection is accomplished particularly advantageously when the detectoris disposed behind an interference filter and/or a cutoff filter (havinga short wave transmission cutoff within the range from λ_(max) toλ_(max) +80 nm) and/or a polarizer.

By means of the abovementioned compounds, it is very simple to detectmarked liquids, even if the phthalocyanines II are present only in aconcentration of about 1 ppm (detection by absorption) or about 5 ppb(detection by fluorescence).

The phthalocyanines of the formula II are highly soluble in the liquidsto be marked. They also have high chemical stability in solution.

The Examples which follow illustrate the invention.

A) Preparation

EXAMPLE 1

56.3 g (0.325 mol) of 30% strength by weight methanolic sodium methoxidesolution were dissolved in 1 l of n-butanol and excess methanol wasdistilled off until a constant boiling point of 117° C. was attained.112.5 g of 3-(3′-methylpiperidin-1-yl)phthalonitrile were then added,and the mixture was stirred under reflux for 6 h. It was then added to1.5 l of methanol, and the mixture was subsequently stirred for 1 h andfiltered with suction. The residue was washed in succession withmethanol, water and acetone and then air dried.

This gave 101.4 g of phthalocyanine of the formula

where PcH₂ is the quadrivalent radical of phthalocyanine whose centralunit is twice hydrogen.

The same method gives the phthalocyanines recited below in Table 1.

TABLE 1 PcMe(R)₄ Ex. No. Me R  2 2H

 3 2H

 4 2H

 5 2H

 6 2H

 7 2H

 8 2H

 9 2H

10 2H

11 2H

12 2H

13 2H

14 2H

15 2H

16 2H

17 2H

18 2H

19 2H

20 2H

21 AlCl

22 AlCl

23 AlCl

24 AlCl

25 AlCl

26 SiCl₂

27 SiCl₂

28 AlOCOCF₃

29 AlOH

30 2H

31 2H

32 2H

33 AlCl

34 AlCl

35 AlCl

36 AlOCOCF₃

37 SiCl₂

B) Application

I. Detection by Absorption in IR Region

Sufficient dye of the formula

was dissolved in one of the liquids mentioned in Table 2 to obtain asolution having a dye content of 10 ppm. The absorption of thesesolutions in the IR region was measured in each case by means of acommercially available spectrometer (1 cm cell).

TABLE 2 Absorption maximum Dye content [ppm] Absorption [nm] Dieselmotor fuel 1.10 762 Unleaded gasoline 1.10 760 Ethanol 1.05 771 Toluene1.15 770

To measure the stability of the dye in storage, the samples were storedfor several weeks at room temperature (RT) and at 50° C., and theabsorption was measured using a commercially available spectrometer.Specifically, the results obtained were as follows:

TABLE 3 Test duration Unleaded (temp.) Ethanol Toluene Diesel motor fuelgasoline 0 time (RT) 1.0535 1.1486 1.0964 1.0993 1 week (RT) 1.06011.152 1.0977 1.0937 2 weeks (RT) 1.0479 1.1484 1.097 1.1014 4 weeks (RT)1.0467 1.1517 1.097 1.098 8 Weeks (RT) 1.0181 1.1443 1.078 1.0869 1 week(50° C.) 1.0467 1.1421 1.016 1.0926 2 weeks (50° C.) 1.0521 1.15381.0917 1.0989 4 weeks (50° C.) 1.043 1.1438 1.0937 1.0864 8 weeks (50°C.) 1.0467 1.1445 1.0455 1.0617

II. Detection by Fluorescence in NIR Region

The marker fluorescence is excited using the emission of a commercialsemiconductor diode laser. The parallel laser beam is directed at thesample in a 1 cm cell. To double the excitation intensity, thetransmitted light beam is reflected by a mirror and passed once morethrough the sample.

The fluorescence light is imaged by means of optical elements (lenssystem) on the detector, a silicon photodiode. The light emitted to therear is likewise directed onto the silicon photodiode by a concavemirror.

Interfering light (scattered excitation light) is removed from thefluorescence light using cutoff and/or interference filters and/or apolarizer (NIR polarization film).

The polarizer is optimized so that the direction of the maximumtransmission is perpendicular to the plane of polarization of theexcitation light.

Sufficient dye of the formula

was dissolved in diesel motor fuel to obtain a solution having a dyecontent of 250 ppb.

This solution was measured by general method II using the followingapparatus parameters:

excitation: semiconductor diode laser of laser wavelength 789 nm; CWpower 2 mW (modulation: 1.9 kHz)

Filter: long-pass interference filter 805 nm.

Photodetector: silicon PIN diode of 1 cm² area. The photocurrent wasdetected using a lock-in amplifier. The essential aspect of thesemeasurements was the stability of the dye in storage at roomtemperature. The measurements obtained are recited in Table 3.

TABLE 3 Time Absorbance Fluorescence signal [weeks] at λ_(max) [nm] (inscale divisions) 0 789 1.96 1 789 1.98 2 789 2.04 3 789 1.90 4 789 1.95

We claim:
 1. A phthalocyanine of formula I′ or I″

wherein: in formula I′, Me is magnesium, zinc, copper, nickel, VO, TiO,AlCl, AlOH, AlOCOCH₃, AlOCOCF₃, SiCl₂ or Si(OH)₂, and wherein in formulaI″, both Y groups are hydrogen ion or lithium ion, and at least four ofthe radicals R¹ to R¹⁶ in each of formulas I′ and I″ are eachindependently of the others a nitrogen-containing heterocyclic radicalwhich is monosubstituted or polysubstituted by C₁-C₄-alkyl, benzyl,phenylethyl or phenyl and is bonded to the phthalocyanine structure viaa ring nitrogen atom of the heterocyclic radical which is a memberselected from the group consisting of pyrrolidinyl, pyrazolidinyl,imidazolidinyl, oxazolidinyl, isoxazolidinyl, piperidinyl, piperazinyl,morpholinyl and thiomorpholinyl, and any remaining radicals R¹ and R¹⁶are each hydrogen, halogen, hydroxysulfonyl of C₁-C₄-dialkylsulfamoyl.2. Phthalocyanines as claimed in claim 1, wherein four of the radicalsR¹ to R¹⁶ are each a heterocyclic radical.
 3. The phthalocyanine asclaimed in claim 1, wherein four of the radicals R¹ to R¹⁶ are each aheterocyclic radical and the remaining radicals R¹ to R¹⁶ are eachhydrogen.
 4. The phthalocyanine as claimed in claim 1, wherein formulaI′ conforms to the formula Ia or lb:

where the radicals R⁴, R⁸, R¹² and R¹⁶ and R², R⁶, R¹⁰ and R¹⁴ are eacha heterocyclic radical and Me is in each case as defined above, andtheir positional isomers in relation to the radicals R⁴, R⁸, R¹² and R¹⁶and also R², R⁶, R¹⁰ and R¹⁴.
 5. The phthalocyanine of claim 1, whereinsaid heterocyclic radical is a member selected from the group consistingof: pyrrolidin-1-yl; 2- or 3-methylpyrrolidin-1-yl;2,4-dimethyl-3-ethylpyrrolidinyl; pyrazolidin-1-yl; 2,-, 3-, 4- or5-methylpyrazolidin-1-yl; imidazolidin-1-yl; 2-, 3-, 4- or5-methylimidazolidin-1-yl; oxaolidin-3-yl; 2-, 4- or5-methyloxazolidin-3-yl; isoxazolidin-2-yl, 3-, 4- or5-methylisoxazolidin-2-yl, piperidin-1-yl, 2-, 3-, 4-methyl-, ethyl- or-benzyl-piperidin-1-yl, 2,6-dimethylpiperidin-1-yl, piperazin-1-yl,4-(C₁-C₄-alkyl)piperazin-1-yl, morpholin-4-yl, thiomorpholin-4-yl orthiomorpholin-4-yl S,S-dioxide.
 6. The phthalocyanine according to claim1, wherein said C₁-C₄-dialkylsulfamoyl is dimethylsulfamoyl,diethylsulfamoyl, dipropylsulfamoyl, diisopropylsulfamoyl,dibutylsulfamoyl or N-methyl-N-ethylsulfamoyl.
 7. A phthalocyanine offormula I′ or I″

wherein: in formula I′, Me is zinc, AlCl, AlOH, AlOCOCH₃, AlOCOCF₃,SiCl₂ or Si(OH)₂, and wherein in formula I″, both Y groups are hydrogenion or lithium ion, and at least four of the radicals R¹ to R¹⁶ in eachof formulas I′ and I″ are each independently of the others anitrogen-containing heterocyclic radical which is monosubstituted orpolysubstituted by C₁-C₄-alkyl, benzyl, phenylethyl or phenyl and isbonded to the phthalocyanine structure via a ring nitrogen atom of theheterocyclic radical which is a member selected from the groupconsisting of pyrrolidinyl, pyrazolidinyl, imidazolidinyl, oxazolidinyl,isoxazolidinyl, piperidinyl, piperazinyl, morpholinyl andthiomorpholinyl, and any remaining radicals R¹ and R¹⁶ are eachhydrogen, halogen, hydroxysulfonyl of C₁-C₄-dialkylsulfamoyl.
 8. Thephthalocyanine as claimed in claim 1, wherein formula I″ conforms to theformula Ia or lb;

where the radicals R⁴, R⁸, R¹² and R¹⁶ and R², R⁶, R¹⁰ and R¹⁴ are eacha heterocyclic radical and Me is in each case as defined above, andtheir positional isomers in relation to the radicals R⁴, R⁸, R¹² and R¹⁶and also R², R⁶, R¹⁰ and R¹⁴.
 9. A method of marking a liquid,comprising: mixing the phthalocyanine of claim 1 into the liquid to bemarked.
 10. The method according to claim 9, wherein said liquid is amineral oil.
 11. A mineral oil comprising at least one phthalocyanine asclaimed in claim 1.